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custom-in-construct

Summary: Custom function may be replaced by in keyword

Category: Idiomatic

Avoid

package policy

import rego.v1

allow if has_value(input.user.roles, "admin")

# This custom function was commonly seen before the introduction
# of the `in` keyword. Avoid it now.
has_value(arr, item) if {
    item == arr[_]
}

Prefer

package policy

import rego.v1

allow if "admin" in input.user.roles

Rationale​

The in keyword was introduced in OPA v0.34.0. Prior to that, it was a common practice to create a custom helper function that would iterate over values of an array in order to check if it contained a provided value. Since the introduction of the in keyword, this is no longer necessary. The in keyword additionally supports sets and maps as the collection type, so using it consistently is recommended.

Configuration Options​

This linter rule provides the following configuration options:

rules:
  idiomatic:
    custom-in-construct:
      # one of "error", "warning", "ignore"
      level: error

Community​

If you think you've found a problem with this rule or its documentation, would like to suggest improvements, new rules, or just talk about Regal in general, please join us in the #regal channel in the Styra Community Slack!